1. Statement of the Technical Field
The invention concerns electronic devices comprising one or more batteries. More particularly, the invention concerns retainers configured for preventing batteries from being dislodged from a battery holder or clip due to external forces (e.g., an impact force produced by dropping the electronic device).
2. Description of the Related Art
Electronic devices which comprise internal circuit components are typically powered by external primary batteries. These external primary batteries are often housed in a battery compartment of the electronic device in a manner enabling an electrical connection between the battery and the internal circuit components. However, it is increasingly desirable to provide these internal circuit components with a back-up battery (e.g., battery 102 shown in FIGS. 1-2). The back-up battery can generally be provided for assuring continued retention of stored information in the event of a power loss from the primary power source.
The back-up battery is generally a low profile battery, such as a coin cell battery. Coin cell batteries are well known to those having ordinary skill in the art, and therefore will not be described herein. The back-up battery is often housed in a battery holder (e.g., battery holder 104 shown in FIGS. 1-2) coupled to a printed circuit board (e.g., printed circuit board 106 shown in FIGS. 1-2) that can be disposed within the electronic device. The battery holder generally has a cup-shape with an insertion space or slot (e.g., slot 108 shown in FIG. 2) configured for receiving the back-up battery (as shown in FIGS. 1-2). The insert space or slot is typically provided on a circumferential edge portion (e.g., edge 110 shown in FIGS. 1-2) of the battery holder. The insert space or slot permits the back-up battery to be removably inserted within a cavity (e.g., cavity 112 shown in FIG. 2) defined by the battery holder. Despite the advantages of the conventional battery holder, it suffers from certain drawbacks. For example, the back-up battery may be dislodged from the battery holder when an external force is applied thereto (as shown in FIG. 2). Such external forces include, but are not limited to, an impact force produced by dropping the electronic device.
A plurality of mechanical retainers have been employed for retaining the back-up battery within the battery holder. Such mechanical retainers include, but are not limited to, clips and locking bars. Despite the advantages of these conventional mechanical retainers, they suffer from certain drawbacks. For example, the clips are thin sheet metal parts formed of a conductive material. The clips are configured to be mechanically coupled to the battery holder. Over time, the clips may become bent or deformed. In such a scenario, the clips can become loose or uncoupled from the battery holder when an external force is applied to the electronic device. If the clips become uncoupled from the battery holders, then the clips may provide shorts in the circuits of the electronic devices. Also, the clips are electronically coupled to the positive terminal of the back-up batteries. In effect, the clips increase the positive surface area of the back-up battery assemblies. One can appreciate that this is undesirable in many applications since the increased positive surface area provides a greater potential of a short circuit. Further, the clips are often lost during battery replacement processes.
The locking bars are generally formed of a conductive material with a dielectric sleeve disposed thereon. The locking bars are costly to manufacture and increase the conductive surface area of a PCB. The locking bars also have a relatively large profile. As such, the locking bars consume a relatively large amount of board space. Further, the locking bars have a relatively complicated assembly. In this regard, it should be understood that the locking bars are coupled to PCBs via mechanical connectors (e.g., screws). In effect, various torque tools are required to couple the locking bars to the PCB. The torque tools ensure a particular screw torque value requirement is met.
In view of the forgoing, there is a need for an improved mechanical retainer that can be used in back-up battery retention applications. The improved mechanical retainer needs to be less expensive to manufacture. The improved mechanical retainer needs to have a relatively easy assembly feature. The improved mechanical retainer needs to consume a relatively small amount of board space and provide a relatively low potential for a short circuit.